Support different types of output

[aayushmau5]

Reason/Context

• Why we need this improvement? Since, this library currently supports showing diff in a JSON format. I think it would be good to have more different ways of showing the output. For example, we can show the output in YAML, HTML or Markdown format.
• How will this change help? This library will have more ways of showing the output, and since, this library will be integrated into AsyncAPI CLI and playground, we will have the ability to show different type of output on those platforms as well.
• What is the motivation? Extend this library :)

Description

• Detailed description: Current JSON format only goes so far, we need to provide more ways to show the diff. For starters, we can show the output in HTML as well as Markdown format. And then, as need arises, we can focus on having other different types of output as well(like YAML, etc.)

• How could it be implemented/designed? The implementation is not really clear right now(I'll be working on that now), but since the diff generates JSON output, we need to convert this JSON output into HTML, Markdown. As for how this HTML, Markdown format will look like, we need to have a detailed discussion on that as well. I'll be working on an initial draft for the output, and from there we can flesh out the design.